1. ISBE-AstraZeneca Strategic Alliance Project 21 Progress Report Thickness mapping of articular hip cartilage Twelfth meeting of the Strategic Alliance Alderley Park, 10 February 2005

2. ISBE-AstraZeneca Strategic Alliance Project 21 Progress Report Background Besides the knee, the hip is the major joint affected by OA. Many studies assessing knee cartilage, still very little in literature on hip (recent report in OA&Cart Aug 2004, Nishii et al measured acetabular cartilage thickness using traction to separate acetabular and femoral cartilage) Hip poses greater challenges than knee due to narrower joint space, spherical morphology, ligament and acetabular fossa Images collected from six normal volunteers (females aged 22-34), weightbearing and non-weightbearing, two occasions

3. ISBE-AstraZeneca Strategic Alliance Project 21 Progress Report T1W FS-FFET2W FFE

4. ISBE-AstraZeneca Strategic Alliance Project 21 Progress Report Steps Segment bone from T2W images, cartilage from T1W images using Endpoint Fit to the bone segmentation using a sphere plus cone model and use the results to define a frame of reference Build a triangulated surface from the cartilage segmentation using code developed for the knee cartilage Produce cartilage thickness maps by finding points of intersection of the triangulated cartilage surface with normals fired from equally spaced points on the bone model sphere Look at weightbearing vs non-weightbearing, reproducibility, inter- subject variation

5. ISBE-AstraZeneca Strategic Alliance Project 21 Progress Report Sphere plus cone fit Axis of cone determines coordinate system on the sphere

6. ISBE-AstraZeneca Strategic Alliance Project 21 Progress Report Cartilage surface construction Uses Tom Williams code developed for knee cartilage

7. ISBE-AstraZeneca Strategic Alliance Project 21 Progress Report Thickness map

8. ISBE-AstraZeneca Strategic Alliance Project 21 Progress Report Difference map Non-weightbearing minus weightbearing

9. ISBE-AstraZeneca Strategic Alliance Project 21 Progress Report Mean thickness in mm SubjectvisitWeight/ Non meanstd 11W2.320.89 N2.390.92 2W2.270.86 N2.410.90 21W2.431.06 N2.531.12 2W2.360.96 N2.431.06

10. ISBE-AstraZeneca Strategic Alliance Project 21 Progress Report Next steps Complete segmentations for remaining subjects Statistical analysis Methods paper? Future look: Improve surface building for structures with high curvature Produce signal intensity maps Develop improved hip protocol at 3T –possible to separate acetabular and femoral cartilage? –thinner slices to reduce partial volume effects at curved edges

11. ISBE-AstraZeneca Strategic Alliance Project 21 Progress Report (Very) preliminary results at 3T